/*
 * Copyright © 2001-2011 Stéphane Raimbault <stephane.raimbault@gmail.com>
 *
 * SPDX-License-Identifier: LGPL-2.1+
 */

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
//#include <fcntl.h>
#include <string.h>

#include <assert.h>

#include "modbus-private.h"

#include "modbus-rtu.h"
#include "modbus-rtu-private.h"

#if HAVE_DECL_TIOCSRS485 || HAVE_DECL_TIOCM_RTS
#include <sys/ioctl.h>
#endif

#if HAVE_DECL_TIOCSRS485
#include <linux/serial.h>
#endif

/* Table of CRC values for high-order byte */
static const uint8_t table_crc_hi[] = {
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
    0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
    0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
    0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
    0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
    0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
    0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
    0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
    0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
    0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
};

/* Table of CRC values for low-order byte */
static const uint8_t table_crc_lo[] = {
    0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
    0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
    0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
    0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
    0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
    0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
    0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
    0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
    0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
    0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
    0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
    0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
    0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
    0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
    0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
    0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
    0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
    0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
    0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
    0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
    0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
    0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,
    0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
    0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
    0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
    0x43, 0x83, 0x41, 0x81, 0x80, 0x40
};

/* Define the slave ID of the remote device to talk in master mode or set the
 * internal slave ID in slave mode */
static int _modbus_set_slave(modbus_t *ctx, int slave)
{
    /* Broadcast address is 0 (MODBUS_BROADCAST_ADDRESS) */
    if (slave >= 0 && slave <= 247) {
        ctx->slave = slave;
    } else {
        errno = EINVAL;
        return -1;
    }

    return 0;
}

/* Builds a RTU request header */
static int _modbus_rtu_build_request_basis(modbus_t *ctx, int function,
                                           int addr, int nb,
                                           uint8_t *req)
{
    assert(ctx->slave != -1);
    req[0] = ctx->slave;
    req[1] = function;
    req[2] = addr >> 8;
    req[3] = addr & 0x00ff;
    req[4] = nb >> 8;
    req[5] = nb & 0x00ff;

    return _MODBUS_RTU_PRESET_REQ_LENGTH;
}

/* Builds a RTU response header */
static int _modbus_rtu_build_response_basis(sft_t *sft, uint8_t *rsp)
{
    /* In this case, the slave is certainly valid because a check is already
     * done in _modbus_rtu_listen */
    rsp[0] = sft->slave;
    rsp[1] = sft->function;

    return _MODBUS_RTU_PRESET_RSP_LENGTH;
}

static uint16_t crc16(uint8_t *buffer, uint16_t buffer_length)
{
    uint8_t crc_hi = 0xFF; /* high CRC byte initialized */
    uint8_t crc_lo = 0xFF; /* low CRC byte initialized */
    unsigned int i; /* will index into CRC lookup */

    /* pass through message buffer */
    while (buffer_length--) {
        i = crc_hi ^ *buffer++; /* calculate the CRC  */
        crc_hi = crc_lo ^ table_crc_hi[i];
        crc_lo = table_crc_lo[i];
    }

    return (crc_hi << 8 | crc_lo);
}

static int _modbus_rtu_prepare_response_tid(const uint8_t *req, int *req_length)
{
    (*req_length) -= _MODBUS_RTU_CHECKSUM_LENGTH;
    /* No TID */
    return 0;
}

static int _modbus_rtu_send_msg_pre(uint8_t *req, int req_length)
{
    uint16_t crc = crc16(req, req_length);
    req[req_length++] = crc >> 8;
    req[req_length++] = crc & 0x00FF;

    return req_length;
}

#if defined(_WIN32)

/* This simple implementation is sort of a substitute of the select() call,
 * working this way: the win32_ser_select() call tries to read some data from
 * the serial port, setting the timeout as the select() call would. Data read is
 * stored into the receive buffer, that is then consumed by the win32_ser_read()
 * call.  So win32_ser_select() does both the event waiting and the reading,
 * while win32_ser_read() only consumes the receive buffer.
 */

static void win32_ser_init(struct win32_ser *ws)
{
    /* Clear everything */
    memset(ws, 0x00, sizeof(struct win32_ser));

    /* Set file handle to invalid */
    ws->fd = INVALID_HANDLE_VALUE;
}

/* FIXME Try to remove length_to_read -> max_len argument, only used by win32 */
static int win32_ser_select(struct win32_ser *ws, int max_len,
                            const struct timeval *tv)
{
    COMMTIMEOUTS comm_to;
    unsigned int msec = 0;

    /* Check if some data still in the buffer to be consumed */
    if (ws->n_bytes > 0) {
        return 1;
    }

    /* Setup timeouts like select() would do.
       FIXME Please someone on Windows can look at this?
       Does it possible to use WaitCommEvent?
       When tv is NULL, MAXDWORD isn't infinite!
     */
    if (tv == NULL) {
        msec = MAXDWORD;
    } else {
        msec = tv->tv_sec * 1000 + tv->tv_usec / 1000;
        if (msec < 1)
            msec = 1;
    }

    comm_to.ReadIntervalTimeout = msec;
    comm_to.ReadTotalTimeoutMultiplier = 0;
    comm_to.ReadTotalTimeoutConstant = msec;
    comm_to.WriteTotalTimeoutMultiplier = 0;
    comm_to.WriteTotalTimeoutConstant = 1000;
    SetCommTimeouts(ws->fd, &comm_to);

    /* Read some bytes */
    if ((max_len > PY_BUF_SIZE) || (max_len < 0)) {
        max_len = PY_BUF_SIZE;
    }

    if (ReadFile(ws->fd, &ws->buf, max_len, &ws->n_bytes, NULL)) {
        /* Check if some bytes available */
        if (ws->n_bytes > 0) {
            /* Some bytes read */
            return 1;
        } else {
            /* Just timed out */
            return 0;
        }
    } else {
        /* Some kind of error */
        return -1;
    }
}

static int win32_ser_read(struct win32_ser *ws, uint8_t *p_msg,
                          unsigned int max_len)
{
    unsigned int n = ws->n_bytes;

    if (max_len < n) {
        n = max_len;
    }

    if (n > 0) {
        memcpy(p_msg, ws->buf, n);
    }

    ws->n_bytes -= n;

    return n;
}
#endif

#if HAVE_DECL_TIOCM_RTS
static void _modbus_rtu_ioctl_rts(modbus_t *ctx, int on)
{
    int fd = ctx->s;
    int flags;

    ioctl(fd, TIOCMGET, &flags);
    if (on) {
        flags |= TIOCM_RTS;
    } else {
        flags &= ~TIOCM_RTS;
    }
    ioctl(fd, TIOCMSET, &flags);
}
#endif

static ssize_t _modbus_rtu_send(modbus_t *ctx, const uint8_t *req, int req_length)
{
//		in_buf_t* dev = ((modbus_rtu_t *)ctx->backend_data)->usr_ctx;
//		return in_buf_send(dev, (void*)req, req_length);
}

static int _modbus_rtu_receive(modbus_t *ctx, uint8_t *req)
{
    int rc;
    modbus_rtu_t *ctx_rtu = ctx->backend_data;

    if (ctx_rtu->confirmation_to_ignore) {
        _modbus_receive_msg(ctx, req, MSG_CONFIRMATION);
        /* Ignore errors and reset the flag */
        ctx_rtu->confirmation_to_ignore = FALSE;
        rc = 0;
        if (ctx->debug) {
            printf("Confirmation to ignore\n");
        }
    } else {
        rc = _modbus_receive_msg(ctx, req, MSG_INDICATION);
        if (rc == 0) {
            /* The next expected message is a confirmation to ignore */
            ctx_rtu->confirmation_to_ignore = TRUE;
        }
    }
    return rc;
}

static ssize_t _modbus_rtu_recv(modbus_t *ctx, uint8_t *rsp, int rsp_length)
{
	/*not use*/
//		return rtu_dev_modbus_recv( ((modbus_rtu_t *)ctx->backend_data)->usr_ctx, rsp, rsp_length);
	
}

static int _modbus_rtu_flush(modbus_t *);

static int _modbus_rtu_pre_check_confirmation(modbus_t *ctx, const uint8_t *req,
                                              const uint8_t *rsp, int rsp_length)
{
    /* Check responding slave is the slave we requested (except for broacast
     * request) */
    if (req[0] != rsp[0] && req[0] != MODBUS_BROADCAST_ADDRESS) {
        if (ctx->debug) {
            fprintf(stderr,
                    "The responding slave %d isn't the requested slave %d\n",
                    rsp[0], req[0]);
        }
        errno = EMBBADSLAVE;
        return -1;
    } else {
        return 0;
    }
}

/* The check_crc16 function shall return 0 is the message is ignored and the
   message length if the CRC is valid. Otherwise it shall return -1 and set
   errno to EMBADCRC. */
static int _modbus_rtu_check_integrity(modbus_t *ctx, uint8_t *msg,
                                       const int msg_length)
{
    uint16_t crc_calculated;
    uint16_t crc_received;
    int slave = msg[0];

    /* Filter on the Modbus unit identifier (slave) in RTU mode to avoid useless
     * CRC computing. */
    if (slave != ctx->slave && slave != MODBUS_BROADCAST_ADDRESS) {
        if (ctx->debug) {
            printf("Request for slave %d ignored (not %d)\n", slave, ctx->slave);
        }
        /* Following call to check_confirmation handles this error */
        return 0;
    }

    crc_calculated = crc16(msg, msg_length - 2);
    crc_received = (msg[msg_length - 2] << 8) | msg[msg_length - 1];

    /* Check CRC of msg */
    if (crc_calculated == crc_received) {
        return msg_length;
    } else {
        if (ctx->debug) {
            fprintf(stderr, "ERROR CRC received 0x%0X != CRC calculated 0x%0X\n",
                    crc_received, crc_calculated);
        }

        if (ctx->error_recovery & MODBUS_ERROR_RECOVERY_PROTOCOL) {
            _modbus_rtu_flush(ctx);
        }
        errno = EMBBADCRC;
        return -1;
    }
}

/* Sets up a serial port for RTU communications */
static int _modbus_rtu_connect(modbus_t *ctx)
{
	
	/*这里不配置串口*/
	
//#if defined(_WIN32)
//    DCB dcb;
//#else
//    struct termios tios;
//    speed_t speed;
//    int flags;
//#endif
//    modbus_rtu_t *ctx_rtu = ctx->backend_data;

//    if (ctx->debug) {
//        printf("Opening %s at %d bauds (%c, %d, %d)\n",
//               ctx_rtu->device, ctx_rtu->baud, ctx_rtu->parity,
//               ctx_rtu->data_bit, ctx_rtu->stop_bit);
//    }

//#if defined(_WIN32)
//    /* Some references here:
//     * http://msdn.microsoft.com/en-us/library/aa450602.aspx
//     */
//    win32_ser_init(&ctx_rtu->w_ser);

//    /* ctx_rtu->device should contain a string like "COMxx:" xx being a decimal
//     * number */
//    ctx_rtu->w_ser.fd = CreateFileA(ctx_rtu->device,
//                                    GENERIC_READ | GENERIC_WRITE,
//                                    0,
//                                    NULL,
//                                    OPEN_EXISTING,
//                                    0,
//                                    NULL);

//    /* Error checking */
//    if (ctx_rtu->w_ser.fd == INVALID_HANDLE_VALUE) {
//        if (ctx->debug) {
//            fprintf(stderr, "ERROR Can't open the device %s (LastError %d)\n",
//                    ctx_rtu->device, (int)GetLastError());
//        }
//        return -1;
//    }

//    /* Save params */
//    ctx_rtu->old_dcb.DCBlength = sizeof(DCB);
//    if (!GetCommState(ctx_rtu->w_ser.fd, &ctx_rtu->old_dcb)) {
//        if (ctx->debug) {
//            fprintf(stderr, "ERROR Error getting configuration (LastError %d)\n",
//                    (int)GetLastError());
//        }
//        CloseHandle(ctx_rtu->w_ser.fd);
//        ctx_rtu->w_ser.fd = INVALID_HANDLE_VALUE;
//        return -1;
//    }

//    /* Build new configuration (starting from current settings) */
//    dcb = ctx_rtu->old_dcb;

//    /* Speed setting */
//    switch (ctx_rtu->baud) {
//    case 110:
//        dcb.BaudRate = CBR_110;
//        break;
//    case 300:
//        dcb.BaudRate = CBR_300;
//        break;
//    case 600:
//        dcb.BaudRate = CBR_600;
//        break;
//    case 1200:
//        dcb.BaudRate = CBR_1200;
//        break;
//    case 2400:
//        dcb.BaudRate = CBR_2400;
//        break;
//    case 4800:
//        dcb.BaudRate = CBR_4800;
//        break;
//    case 9600:
//        dcb.BaudRate = CBR_9600;
//        break;
//    case 14400:
//        dcb.BaudRate = CBR_14400;
//        break;
//    case 19200:
//        dcb.BaudRate = CBR_19200;
//        break;
//    case 38400:
//        dcb.BaudRate = CBR_38400;
//        break;
//    case 57600:
//        dcb.BaudRate = CBR_57600;
//        break;
//    case 115200:
//        dcb.BaudRate = CBR_115200;
//        break;
//    case 230400:
//        /* CBR_230400 - not defined */
//        dcb.BaudRate = 230400;
//        break;
//    case 250000:
//        dcb.BaudRate = 250000;
//        break;
//    case 460800:
//        dcb.BaudRate = 460800;
//        break;
//    case 500000:
//        dcb.BaudRate = 500000;
//        break;
//    case 921600:
//        dcb.BaudRate = 921600;
//        break;
//    case 1000000:
//        dcb.BaudRate = 1000000;
//        break;
//    default:
//        dcb.BaudRate = CBR_9600;
//        if (ctx->debug) {
//            fprintf(stderr, "WARNING Unknown baud rate %d for %s (B9600 used)\n",
//                    ctx_rtu->baud, ctx_rtu->device);
//        }
//    }

//    /* Data bits */
//    switch (ctx_rtu->data_bit) {
//    case 5:
//        dcb.ByteSize = 5;
//        break;
//    case 6:
//        dcb.ByteSize = 6;
//        break;
//    case 7:
//        dcb.ByteSize = 7;
//        break;
//    case 8:
//    default:
//        dcb.ByteSize = 8;
//        break;
//    }

//    /* Stop bits */
//    if (ctx_rtu->stop_bit == 1)
//        dcb.StopBits = ONESTOPBIT;
//    else /* 2 */
//        dcb.StopBits = TWOSTOPBITS;

//    /* Parity */
//    if (ctx_rtu->parity == 'N') {
//        dcb.Parity = NOPARITY;
//        dcb.fParity = FALSE;
//    } else if (ctx_rtu->parity == 'E') {
//        dcb.Parity = EVENPARITY;
//        dcb.fParity = TRUE;
//    } else {
//        /* odd */
//        dcb.Parity = ODDPARITY;
//        dcb.fParity = TRUE;
//    }

//    /* Hardware handshaking left as default settings retrieved */

//    /* No software handshaking */
//    dcb.fTXContinueOnXoff = TRUE;
//    dcb.fOutX = FALSE;
//    dcb.fInX = FALSE;

//    /* Binary mode (it's the only supported on Windows anyway) */
//    dcb.fBinary = TRUE;

//    /* Don't want errors to be blocking */
//    dcb.fAbortOnError = FALSE;

//    /* Setup port */
//    if (!SetCommState(ctx_rtu->w_ser.fd, &dcb)) {
//        if (ctx->debug) {
//            fprintf(stderr, "ERROR Error setting new configuration (LastError %d)\n",
//                    (int)GetLastError());
//        }
//        CloseHandle(ctx_rtu->w_ser.fd);
//        ctx_rtu->w_ser.fd = INVALID_HANDLE_VALUE;
//        return -1;
//    }
//#else
//    /* The O_NOCTTY flag tells UNIX that this program doesn't want
//       to be the "controlling terminal" for that port. If you
//       don't specify this then any input (such as keyboard abort
//       signals and so forth) will affect your process

//       Timeouts are ignored in canonical input mode or when the
//       NDELAY option is set on the file via open or fcntl */
//    flags = O_RDWR | O_NOCTTY | O_NDELAY | O_EXCL;
//#ifdef O_CLOEXEC
//    flags |= O_CLOEXEC;
//#endif

//    ctx->s = open(ctx_rtu->device, flags);
//    if (ctx->s == -1) {
//        if (ctx->debug) {
//            fprintf(stderr, "ERROR Can't open the device %s (%s)\n",
//                    ctx_rtu->device, strerror(errno));
//        }
//        return -1;
//    }

//    /* Save */
//    tcgetattr(ctx->s, &ctx_rtu->old_tios);

//    memset(&tios, 0, sizeof(struct termios));

//    /* C_ISPEED     Input baud (new interface)
//       C_OSPEED     Output baud (new interface)
//    */
//    switch (ctx_rtu->baud) {
//    case 110:
//        speed = B110;
//        break;
//    case 300:
//        speed = B300;
//        break;
//    case 600:
//        speed = B600;
//        break;
//    case 1200:
//        speed = B1200;
//        break;
//    case 2400:
//        speed = B2400;
//        break;
//    case 4800:
//        speed = B4800;
//        break;
//    case 9600:
//        speed = B9600;
//        break;
//    case 19200:
//        speed = B19200;
//        break;
//    case 38400:
//        speed = B38400;
//        break;
//#ifdef B57600
//    case 57600:
//        speed = B57600;
//        break;
//#endif
//#ifdef B115200
//    case 115200:
//        speed = B115200;
//        break;
//#endif
//#ifdef B230400
//    case 230400:
//        speed = B230400;
//        break;
//#endif
//#ifdef B460800
//    case 460800:
//        speed = B460800;
//        break;
//#endif
//#ifdef B500000
//    case 500000:
//        speed = B500000;
//        break;
//#endif
//#ifdef B576000
//    case 576000:
//        speed = B576000;
//        break;
//#endif
//#ifdef B921600
//    case 921600:
//        speed = B921600;
//        break;
//#endif
//#ifdef B1000000
//    case 1000000:
//        speed = B1000000;
//        break;
//#endif
//#ifdef B1152000
//   case 1152000:
//        speed = B1152000;
//        break;
//#endif
//#ifdef B1500000
//    case 1500000:
//        speed = B1500000;
//        break;
//#endif
//#ifdef B2500000
//    case 2500000:
//        speed = B2500000;
//        break;
//#endif
//#ifdef B3000000
//    case 3000000:
//        speed = B3000000;
//        break;
//#endif
//#ifdef B3500000
//    case 3500000:
//        speed = B3500000;
//        break;
//#endif
//#ifdef B4000000
//    case 4000000:
//        speed = B4000000;
//        break;
//#endif
//    default:
//        speed = B9600;
//        if (ctx->debug) {
//            fprintf(stderr,
//                    "WARNING Unknown baud rate %d for %s (B9600 used)\n",
//                    ctx_rtu->baud, ctx_rtu->device);
//        }
//    }

//    /* Set the baud rate */
//    if ((cfsetispeed(&tios, speed) < 0) ||
//        (cfsetospeed(&tios, speed) < 0)) {
//        close(ctx->s);
//        ctx->s = -1;
//        return -1;
//    }

//    /* C_CFLAG      Control options
//       CLOCAL       Local line - do not change "owner" of port
//       CREAD        Enable receiver
//    */
//    tios.c_cflag |= (CREAD | CLOCAL);
//    /* CSIZE, HUPCL, CRTSCTS (hardware flow control) */

//    /* Set data bits (5, 6, 7, 8 bits)
//       CSIZE        Bit mask for data bits
//    */
//    tios.c_cflag &= ~CSIZE;
//    switch (ctx_rtu->data_bit) {
//    case 5:
//        tios.c_cflag |= CS5;
//        break;
//    case 6:
//        tios.c_cflag |= CS6;
//        break;
//    case 7:
//        tios.c_cflag |= CS7;
//        break;
//    case 8:
//    default:
//        tios.c_cflag |= CS8;
//        break;
//    }

//    /* Stop bit (1 or 2) */
//    if (ctx_rtu->stop_bit == 1)
//        tios.c_cflag &=~ CSTOPB;
//    else /* 2 */
//        tios.c_cflag |= CSTOPB;

//    /* PARENB       Enable parity bit
//       PARODD       Use odd parity instead of even */
//    if (ctx_rtu->parity == 'N') {
//        /* None */
//        tios.c_cflag &=~ PARENB;
//    } else if (ctx_rtu->parity == 'E') {
//        /* Even */
//        tios.c_cflag |= PARENB;
//        tios.c_cflag &=~ PARODD;
//    } else {
//        /* Odd */
//        tios.c_cflag |= PARENB;
//        tios.c_cflag |= PARODD;
//    }

//    /* Read the man page of termios if you need more information. */

//    /* This field isn't used on POSIX systems
//       tios.c_line = 0;
//    */

//    /* C_LFLAG      Line options

//       ISIG Enable SIGINTR, SIGSUSP, SIGDSUSP, and SIGQUIT signals
//       ICANON       Enable canonical input (else raw)
//       XCASE        Map uppercase \lowercase (obsolete)
//       ECHO Enable echoing of input characters
//       ECHOE        Echo erase character as BS-SP-BS
//       ECHOK        Echo NL after kill character
//       ECHONL       Echo NL
//       NOFLSH       Disable flushing of input buffers after
//       interrupt or quit characters
//       IEXTEN       Enable extended functions
//       ECHOCTL      Echo control characters as ^char and delete as ~?
//       ECHOPRT      Echo erased character as character erased
//       ECHOKE       BS-SP-BS entire line on line kill
//       FLUSHO       Output being flushed
//       PENDIN       Retype pending input at next read or input char
//       TOSTOP       Send SIGTTOU for background output

//       Canonical input is line-oriented. Input characters are put
//       into a buffer which can be edited interactively by the user
//       until a CR (carriage return) or LF (line feed) character is
//       received.

//       Raw input is unprocessed. Input characters are passed
//       through exactly as they are received, when they are
//       received. Generally you'll deselect the ICANON, ECHO,
//       ECHOE, and ISIG options when using raw input
//    */

//    /* Raw input */
//    tios.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);

//    /* C_IFLAG      Input options

//       Constant     Description
//       INPCK        Enable parity check
//       IGNPAR       Ignore parity errors
//       PARMRK       Mark parity errors
//       ISTRIP       Strip parity bits
//       IXON Enable software flow control (outgoing)
//       IXOFF        Enable software flow control (incoming)
//       IXANY        Allow any character to start flow again
//       IGNBRK       Ignore break condition
//       BRKINT       Send a SIGINT when a break condition is detected
//       INLCR        Map NL to CR
//       IGNCR        Ignore CR
//       ICRNL        Map CR to NL
//       IUCLC        Map uppercase to lowercase
//       IMAXBEL      Echo BEL on input line too long
//    */
//    if (ctx_rtu->parity == 'N') {
//        /* None */
//        tios.c_iflag &= ~INPCK;
//    } else {
//        tios.c_iflag |= INPCK;
//    }

//    /* Software flow control is disabled */
//    tios.c_iflag &= ~(IXON | IXOFF | IXANY);

//    /* C_OFLAG      Output options
//       OPOST        Postprocess output (not set = raw output)
//       ONLCR        Map NL to CR-NL

//       ONCLR ant others needs OPOST to be enabled
//    */

//    /* Raw ouput */
//    tios.c_oflag &=~ OPOST;

//    /* C_CC         Control characters
//       VMIN         Minimum number of characters to read
//       VTIME        Time to wait for data (tenths of seconds)

//       UNIX serial interface drivers provide the ability to
//       specify character and packet timeouts. Two elements of the
//       c_cc array are used for timeouts: VMIN and VTIME. Timeouts
//       are ignored in canonical input mode or when the NDELAY
//       option is set on the file via open or fcntl.

//       VMIN specifies the minimum number of characters to read. If
//       it is set to 0, then the VTIME value specifies the time to
//       wait for every character read. Note that this does not mean
//       that a read call for N bytes will wait for N characters to
//       come in. Rather, the timeout will apply to the first
//       character and the read call will return the number of
//       characters immediately available (up to the number you
//       request).

//       If VMIN is non-zero, VTIME specifies the time to wait for
//       the first character read. If a character is read within the
//       time given, any read will block (wait) until all VMIN
//       characters are read. That is, once the first character is
//       read, the serial interface driver expects to receive an
//       entire packet of characters (VMIN bytes total). If no
//       character is read within the time allowed, then the call to
//       read returns 0. This method allows you to tell the serial
//       driver you need exactly N bytes and any read call will
//       return 0 or N bytes. However, the timeout only applies to
//       the first character read, so if for some reason the driver
//       misses one character inside the N byte packet then the read
//       call could block forever waiting for additional input
//       characters.

//       VTIME specifies the amount of time to wait for incoming
//       characters in tenths of seconds. If VTIME is set to 0 (the
//       default), reads will block (wait) indefinitely unless the
//       NDELAY option is set on the port with open or fcntl.
//    */
//    /* Unused because we use open with the NDELAY option */
//    tios.c_cc[VMIN] = 0;
//    tios.c_cc[VTIME] = 0;

//    if (tcsetattr(ctx->s, TCSANOW, &tios) < 0) {
//        close(ctx->s);
//        ctx->s = -1;
//        return -1;
//    }
//#endif

    return 0;
}

int modbus_rtu_set_serial_mode(modbus_t *ctx, int mode)
{
    if (ctx == NULL) {
        errno = EINVAL;
        return -1;
    }

    if (ctx->backend->backend_type == _MODBUS_BACKEND_TYPE_RTU) {
#if HAVE_DECL_TIOCSRS485
        modbus_rtu_t *ctx_rtu = ctx->backend_data;
        struct serial_rs485 rs485conf;
        memset(&rs485conf, 0x0, sizeof(struct serial_rs485));

        if (mode == MODBUS_RTU_RS485) {
            rs485conf.flags = SER_RS485_ENABLED;
            if (ioctl(ctx->s, TIOCSRS485, &rs485conf) < 0) {
                return -1;
            }

            ctx_rtu->serial_mode = MODBUS_RTU_RS485;
            return 0;
        } else if (mode == MODBUS_RTU_RS232) {
            /* Turn off RS485 mode only if required */
            if (ctx_rtu->serial_mode == MODBUS_RTU_RS485) {
                /* The ioctl call is avoided because it can fail on some RS232 ports */
                if (ioctl(ctx->s, TIOCSRS485, &rs485conf) < 0) {
                    return -1;
                }
            }
            ctx_rtu->serial_mode = MODBUS_RTU_RS232;
            return 0;
        }
#else
        if (ctx->debug) {
            fprintf(stderr, "This function isn't supported on your platform\n");
        }
        errno = ENOTSUP;
        return -1;
#endif
    }

    /* Wrong backend and invalid mode specified */
    errno = EINVAL;
    return -1;
}

int modbus_rtu_get_serial_mode(modbus_t *ctx)
{
    if (ctx == NULL) {
        errno = EINVAL;
        return -1;
    }

    if (ctx->backend->backend_type == _MODBUS_BACKEND_TYPE_RTU) {
#if HAVE_DECL_TIOCSRS485
        modbus_rtu_t *ctx_rtu = ctx->backend_data;
        return ctx_rtu->serial_mode;
#else
        if (ctx->debug) {
            fprintf(stderr, "This function isn't supported on your platform\n");
        }
        errno = ENOTSUP;
        return -1;
#endif
    } else {
        errno = EINVAL;
        return -1;
    }
}

int modbus_rtu_get_rts(modbus_t *ctx)
{
    if (ctx == NULL) {
        errno = EINVAL;
        return -1;
    }

    if (ctx->backend->backend_type == _MODBUS_BACKEND_TYPE_RTU) {
#if HAVE_DECL_TIOCM_RTS
        modbus_rtu_t *ctx_rtu = ctx->backend_data;
        return ctx_rtu->rts;
#else
        if (ctx->debug) {
            fprintf(stderr, "This function isn't supported on your platform\n");
        }
        errno = ENOTSUP;
        return -1;
#endif
    } else {
        errno = EINVAL;
        return -1;
    }
}

int modbus_rtu_set_rts(modbus_t *ctx, int mode)
{
    if (ctx == NULL) {
        errno = EINVAL;
        return -1;
    }

    if (ctx->backend->backend_type == _MODBUS_BACKEND_TYPE_RTU) {
#if HAVE_DECL_TIOCM_RTS
        modbus_rtu_t *ctx_rtu = ctx->backend_data;

        if (mode == MODBUS_RTU_RTS_NONE || mode == MODBUS_RTU_RTS_UP ||
            mode == MODBUS_RTU_RTS_DOWN) {
            ctx_rtu->rts = mode;

            /* Set the RTS bit in order to not reserve the RS485 bus */
            ctx_rtu->set_rts(ctx, ctx_rtu->rts != MODBUS_RTU_RTS_UP);

            return 0;
        } else {
            errno = EINVAL;
            return -1;
        }
#else
        if (ctx->debug) {
            fprintf(stderr, "This function isn't supported on your platform\n");
        }
        errno = ENOTSUP;
        return -1;
#endif
    }
    /* Wrong backend or invalid mode specified */
    errno = EINVAL;
    return -1;
}

int modbus_rtu_set_custom_rts(modbus_t *ctx, void (*set_rts) (modbus_t *ctx, int on))
{
    if (ctx == NULL) {
        errno = EINVAL;
        return -1;
    }

    if (ctx->backend->backend_type == _MODBUS_BACKEND_TYPE_RTU) {
#if HAVE_DECL_TIOCM_RTS
        modbus_rtu_t *ctx_rtu = ctx->backend_data;
        ctx_rtu->set_rts = set_rts;
        return 0;
#else
        if (ctx->debug) {
            fprintf(stderr, "This function isn't supported on your platform\n");
        }
        errno = ENOTSUP;
        return -1;
#endif
    } else {
        errno = EINVAL;
        return -1;
    }
}

int modbus_rtu_get_rts_delay(modbus_t *ctx)
{
    if (ctx == NULL) {
        errno = EINVAL;
        return -1;
    }

    if (ctx->backend->backend_type == _MODBUS_BACKEND_TYPE_RTU) {
#if HAVE_DECL_TIOCM_RTS
        modbus_rtu_t *ctx_rtu;
        ctx_rtu = (modbus_rtu_t *)ctx->backend_data;
        return ctx_rtu->rts_delay;
#else
        if (ctx->debug) {
            fprintf(stderr, "This function isn't supported on your platform\n");
        }
        errno = ENOTSUP;
        return -1;
#endif
    } else {
        errno = EINVAL;
        return -1;
    }
}

int modbus_rtu_set_rts_delay(modbus_t *ctx, int us)
{
    if (ctx == NULL || us < 0) {
        errno = EINVAL;
        return -1;
    }

    if (ctx->backend->backend_type == _MODBUS_BACKEND_TYPE_RTU) {
#if HAVE_DECL_TIOCM_RTS
        modbus_rtu_t *ctx_rtu;
        ctx_rtu = (modbus_rtu_t *)ctx->backend_data;
        ctx_rtu->rts_delay = us;
        return 0;
#else
        if (ctx->debug) {
            fprintf(stderr, "This function isn't supported on your platform\n");
        }
        errno = ENOTSUP;
        return -1;
#endif
    } else {
        errno = EINVAL;
        return -1;
    }
}

static void _modbus_rtu_close(modbus_t *ctx)
{
    /* Restore line settings and close file descriptor in RTU mode */
    modbus_rtu_t *ctx_rtu = ctx->backend_data;

//#if defined(_WIN32)
//    /* Revert settings */
//    if (!SetCommState(ctx_rtu->w_ser.fd, &ctx_rtu->old_dcb) && ctx->debug) {
//        fprintf(stderr, "ERROR Couldn't revert to configuration (LastError %d)\n",
//                (int)GetLastError());
//    }

//    if (!CloseHandle(ctx_rtu->w_ser.fd) && ctx->debug) {
//        fprintf(stderr, "ERROR Error while closing handle (LastError %d)\n",
//                (int)GetLastError());
//    }
//#else
//    if (ctx->s != -1) {
//        tcsetattr(ctx->s, TCSANOW, &ctx_rtu->old_tios);
//        close(ctx->s);
//        ctx->s = -1;
//    }
//#endif
}

static int _modbus_rtu_flush(modbus_t *ctx)
{
//#if defined(_WIN32)
//    modbus_rtu_t *ctx_rtu = ctx->backend_data;
//    ctx_rtu->w_ser.n_bytes = 0;
//    return (PurgeComm(ctx_rtu->w_ser.fd, PURGE_RXCLEAR) == FALSE);
//#else
//    return tcflush(ctx->s, TCIOFLUSH);
//#endif
}

//static int _modbus_rtu_select(modbus_t *ctx, fd_set *rset,
//                              struct timeval *tv, int length_to_read)
//{
//    int s_rc;
//#if defined(_WIN32)
//    s_rc = win32_ser_select(&((modbus_rtu_t *)ctx->backend_data)->w_ser,
//                            length_to_read, tv);
//    if (s_rc == 0) {
//        errno = ETIMEDOUT;
//        return -1;
//    }

//    if (s_rc < 0) {
//        return -1;
//    }
//#else
//    while ((s_rc = select(ctx->s+1, rset, NULL, NULL, tv)) == -1) {
//        if (errno == EINTR) {
//            if (ctx->debug) {
//                fprintf(stderr, "A non blocked signal was caught\n");
//            }
//            /* Necessary after an error */
//            FD_ZERO(rset);
//            FD_SET(ctx->s, rset);
//        } else {
//            return -1;
//        }
//    }

//    if (s_rc == 0) {
//        /* Timeout */
//        errno = ETIMEDOUT;
//        return -1;
//    }
//#endif

//    return s_rc;
/*rtu 不使用select*/
//	return 0;
//}

static void _modbus_rtu_free(modbus_t *ctx) {
    free(((modbus_rtu_t*)ctx->backend_data)->device);
    free(ctx->backend_data);
    free(ctx);
}

 modbus_backend_t _modbus_rtu_backend = {
    _MODBUS_BACKEND_TYPE_RTU,
    _MODBUS_RTU_HEADER_LENGTH,
    _MODBUS_RTU_CHECKSUM_LENGTH,
    MODBUS_RTU_MAX_ADU_LENGTH,
    _modbus_set_slave,
    _modbus_rtu_build_request_basis,
    _modbus_rtu_build_response_basis,
    _modbus_rtu_prepare_response_tid,
    _modbus_rtu_send_msg_pre,
    _modbus_rtu_send,
    _modbus_rtu_receive,
    _modbus_rtu_recv,
    _modbus_rtu_check_integrity,
    _modbus_rtu_pre_check_confirmation,
    _modbus_rtu_connect,
    _modbus_rtu_close,
    _modbus_rtu_flush,
//    _modbus_rtu_select,
    _modbus_rtu_free
};

modbus_t* modbus_new_rtu(void* usr_ctx, const char *device,
                         int baud, char parity, int data_bit,
                         int stop_bit)
{
    modbus_t *ctx;
    modbus_rtu_t *ctx_rtu;

    /* Check device argument */
    if (device == NULL || *device == 0) {
        fprintf(stderr, "The device string is empty\n");
        errno = EINVAL;
        return NULL;
    }

    /* Check baud argument */
    if (baud == 0) {
        fprintf(stderr, "The baud rate value must not be zero\n");
        errno = EINVAL;
        return NULL;
    }

    ctx = (modbus_t *)malloc(sizeof(modbus_t));
    _modbus_init_common(ctx);
    ctx->backend = &_modbus_rtu_backend;
    ctx->backend_data = (modbus_rtu_t *)malloc(sizeof(modbus_rtu_t));
    ctx_rtu = (modbus_rtu_t *)ctx->backend_data;
    ctx_rtu->device = NULL;

    /* Device name and \0 */
    ctx_rtu->device = (char *)malloc((strlen(device) + 1) * sizeof(char));
    strcpy(ctx_rtu->device, device);

    ctx_rtu->baud = baud;
    if (parity == 'N' || parity == 'E' || parity == 'O') {
        ctx_rtu->parity = parity;
    } else {
        modbus_free(ctx);
        errno = EINVAL;
        return NULL;
    }
    ctx_rtu->data_bit = data_bit;
    ctx_rtu->stop_bit = stop_bit;

#if HAVE_DECL_TIOCSRS485
    /* The RS232 mode has been set by default */
    ctx_rtu->serial_mode = MODBUS_RTU_RS232;
#endif

#if HAVE_DECL_TIOCM_RTS
    /* The RTS use has been set by default */
    ctx_rtu->rts = MODBUS_RTU_RTS_NONE;

    /* Calculate estimated time in micro second to send one byte */
    ctx_rtu->onebyte_time = 1000000 * (1 + data_bit + (parity == 'N' ? 0 : 1) + stop_bit) / baud;

    /* The internal function is used by default to set RTS */
    ctx_rtu->set_rts = _modbus_rtu_ioctl_rts;

    /* The delay before and after transmission when toggling the RTS pin */
    ctx_rtu->rts_delay = ctx_rtu->onebyte_time;
#endif

    ctx_rtu->confirmation_to_ignore = FALSE;
		
		/*add usrctx to rtu backend*/
		ctx_rtu->usr_ctx = usr_ctx;
    return ctx;
}







